Changeset 55155

Timestamp:

01/27/2023 10:12:37 PM (21 months ago)

Author:

flixos90

Message:

Editor: Use a non-persistent object cache in wp_get_global_settings().

This changeset is part of a greater effort to enhance the caching strategy for theme.json based data. Similar to [55138] and [55148], the cache is currently ignored when WP_DEBUG is on to avoid interrupting the theme developer's workflow.

This addition of a non-persistent cache results in a significant performance improvement for the overall load time of WordPress, with the Server-Timing load metric being ~8% faster and Time to First Byte being 25+% faster than before.

Props oandregal, spacedmonkey, hellofromtonya, flixos90, azaozz, aristath.
Fixes #57502.

File:

• trunk/src/wp-includes/global-styles-and-settings.php (modified) (2 diffs)

trunk/src/wp-includes/global-styles-and-settings.php

@@ -26 +26 @@
 function wp_get_global_settings( $path = array(), $context = array() ) {
     if ( ! empty( $context['block_name'] ) ) {
-        $path = array_merge( array( 'blocks', $context['block_name'] ), $path );
-    }
-
+        $new_path = array( 'blocks', $context['block_name'] );
+        foreach ( $path as $subpath ) {
+            $new_path[] = $subpath;
+        }
+        $path = $new_path;
+    }
+
+    /*
+     * This is the default value when no origin is provided or when it is 'all'.
+     *
+     * The $origin is used as part of the cache key. Changes here need to account
+     * for clearing the cache appropriately.
+     */
     $origin = 'custom';
-    if ( isset( $context['origin'] ) && 'base' === $context['origin'] ) {
+    if (
+        ! wp_theme_has_theme_json() ||
+        ( isset( $context['origin'] ) && 'base' === $context['origin'] )
+    ) {
         $origin = 'theme';
     }
 
-    $settings = WP_Theme_JSON_Resolver::get_merged_data( $origin )->get_settings();
+    /*
+     * By using the 'theme_json' group, this data is marked to be non-persistent across requests.
+     * See `wp_cache_add_non_persistent_groups` in src/wp-includes/load.php and other places.
+     *
+     * The rationale for this is to make sure derived data from theme.json
+     * is always fresh from the potential modifications done via hooks
+     * that can use dynamic data (modify the stylesheet depending on some option,
+     * settings depending on user permissions, etc.).
+     * See some of the existing hooks to modify theme.json behaviour:
+     * https://make.wordpress.org/core/2022/10/10/filters-for-theme-json-data/
+     *
+     * A different alternative considered was to invalidate the cache upon certain
+     * events such as options add/update/delete, user meta, etc.
+     * It was judged not enough, hence this approach.
+     * See https://github.com/WordPress/gutenberg/pull/45372
+     */
+    $cache_group = 'theme_json';
+    $cache_key   = 'wp_get_global_settings_' . $origin;
+
+    /*
+     * Ignore cache when `WP_DEBUG` is enabled, so it doesn't interfere with the theme
+     * developer's workflow.
+     *
+     * @todo Replace `WP_DEBUG` once an "in development mode" check is available in Core.
+     */
+    $can_use_cached = ! WP_DEBUG;
+
+    $settings = false;
+    if ( $can_use_cached ) {
+        $settings = wp_cache_get( $cache_key, $cache_group );
+    }
+
+    if ( false === $settings ) {
+        $settings = WP_Theme_JSON_Resolver::get_merged_data( $origin )->get_settings();
+        if ( $can_use_cached ) {
+            wp_cache_set( $cache_key, $settings, $cache_group );
+        }
+    }
 
     return _wp_array_get( $settings, $path, $settings );
@@ -318 +368 @@
 function wp_clean_theme_json_cache() {
     wp_cache_delete( 'wp_get_global_stylesheet', 'theme_json' );
+    wp_cache_delete( 'wp_get_global_settings_custom', 'theme_json' );
+    wp_cache_delete( 'wp_get_global_settings_theme', 'theme_json' );
     WP_Theme_JSON_Resolver::clean_cached_data();
 }